402 Mr. W. Swainsou on the Specific Characters 



state ; but two or three adult specimens have recently been 

 brought to this country from the coast of Peru. Its size is 

 nearly equal to Strombus Gigas, but in appearance it resem- 

 bles a Doliim ; the outer lip is dilated only on its upper 

 part. Mr. Broderip is in possession of the finest specimen 

 I have yet seen, and he suggested to me the very appro- 

 priate name which I have here given it. 



3. StrOiMBUS integer. 



S. testa nodosa ; labii exterioris subinflexi, supra oblique ro- 

 tundati, integri, ad spiram annexi, margine externo recto ; 

 apertura laevi, alba. 



Shell nodulous; outer lip sub-inflexed, above obliquely round- 

 ed, entire, attached to the spire, with the exterior margin 

 straight; aperture smooth, white. 



Resembling in habit S. Accipiter, but is smaller, and the spire 

 more lengthened. The exterior margin of the outer lip, 

 uistead of being curved outwards, is perfectly straight. 

 This shell has long existed in my father's collection, but 

 my recent possession of another specimen has removed the 

 doubts I had entertained of its being a distinct species. 



4. Unio cimeatus. 



U. testa transversun cmieata, antice oblique truncata; den- 

 tibus lateralibus brevissimis, crenatis. 



Shell transversely wedgeshaped ; anterior side obliquely trun- 

 cate ; lateral teeth very short, crenated. 



Inhabits North America. Mus. nost. 



This Unto (for such, notwithstanding its peculiar form, I con- 

 sider it to be) is totally unlike any other species yet dis- 

 covered. If the shell is placed perpendicularly, so that it 

 rests on the posterior end, it presents the perfect appearance 

 of a thick wedge. It is a small species ; the cardinal teeth 

 resemble those of U. pictorum ; and the lateral teeth (from 

 the abrupt truncation of the anterior side) are very short. 



5. Ampullaria co7iica. 



A. testa ovato-globosa, laevi ; basi contracta ; spira crassa, 

 producta, conica ; umbilico obsoleto, basali ; aperturaj mar- 

 gine sulcato ; operculo testaceo. 



Shell ovato-globose, smooth, base contracted ; spire thick, pro- 

 duced, conic; umbilicus obsolete, placed near the base; 

 margin of the aperture grooved ; operculum testaceous. 



The umbilicus in this Ampullaria is quite closed, and is si- 

 tuated nearer to the base of the aperture than that of any 

 other species. The spire also is thicker and more elevated- 

 It is usually of a beautiful olive green colour without bands. 

 The operculum of a specimen before me is testaceous. 



G. Ancilla 



